For more than a century the use of a coil spring non-rotatably attached at one end to a first bracket and non-rotatably attached at its other end to an adjusting member rotatably mounted in a second bracket has been a well known practice in the manufacture of return springs for doors and gates. Many ways have been devised for making the necessary locking connections between the ends of the springs and the associated mounting members. For example, U.S. Pat. No. 137,770 discloses a return spring assembly in which the end members are externally threaded and the end turns of the spring are threaded thereover. U.S. Pat. No. 646,223 discloses the use of a cross slot in the end member for receiving the bent-in end turn of the spring, and U.S. Pat. No. 698,744 discloses a similar spring locking arrangement. Such locking systems are relatively expensive, and they are difficult to repair and maintain. Consequently, the door and gate springs of this general type which are now on the market utilize a cylindrical stud which is press-fitted into the corresponding end of the spring to provide a fixed, non-rotatable connection between the stud and the spring. The studs are in turn attached to the mounting brackets. In many cases, however, the desired non-rotatable connection has not been achieved because if the diameters of the studs are only slightly less than the specified size, rotational slippage will occur when torque is applied to the adjusting studs. Moreover, relatively close dimensional tolerances must be specified to permit assembly of the parts and still assure a non-rotatable connection between the stud and spring.